Oil burner system



April 4, 1967 G. F. DIBERT 3,312,256

OIL BURNER SYSTEM Filed Sept. vl0, 1965 3 Sheets-Sheet l Q -BY .Tm E H eww# :wm N XNNN iw ::EEE: mm QN! om HWNN mmNUSNN lvm m @Uf :23:2::12E: mw@ X e Qmw www ZWN L S Il Illf llnll Il! Il Wl J Nw \Q\ \Qw N\\ .\v`QN y N\ www \P||/Q\ SN www #QQN\ April 4, 1967 G. F. DIBER-r OIL BURNER SYSTEM Filed Sept. l0, 1965 s sheets-sheet 2 IN VEN TOR 1r. r e .1m D E e g r O e.

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G. F. DIBERT OIL BURNER SYSTEM April 4, 1967 Filed Sept. l0, 1965 5 Sheets-Sheet 3 George F Dibelffl1 NVENTOR BY @@@QM Hgeni United States Patent O 3,312,266 OIL BURNER SYSTEM George F. Dibert, 8335 SE. 7th Ave., Portland, Oreg. 97202 Filed sept. 10, 196s, ser. No. 486,485 12 Claims. (Cl. 158-28) This invention relates to oil burners, and more particularly to oil burner systems of the high pressure type.

It is the principal object of the present invention to provide an oil burner system which is character-ized by being capable of ring light, heavy, crude, or crankcase oils under a wide variety of conditions while providing instant ignition, uniform firing and minimum smoke.

Another important object of this invention is the provision of an oil burner system of the class described which includes meansrfor continuouslystripping Vthe fuel oil of entrapped air and volatile oil and gas fractions to insure constant and uniform pump operation, and to remove such volatiles from the proximity of the burner system to insure maximum safety of operation.

Still another important object of the present invention is to provide oi-l burner system which affords the selective firing of fuel oil at two different rates of feed.

Another important object of the present invention is the provision of an oil burner system which not only affords the firing of fuel oil at two different rates of feed, but

also provides automatic adjustment of the air supply to proper proportions for each feed rate of oil for optimum combustion at Iboth feed rates.

A further important object of the present invention is the provision 4of an oil burner system in which means is included for automatically adjusting the air supply in accordance with variations in draft conditions in the firing chamber with which the burner is associated.

A still further important object of the present invention is the provision of an oil burner syste-m Whi-ch is of simplified construction, is easy to install, requires a minimum of maintenance and is simple to adjust to optimum firing eciency.

The foregoing and other objects and advantages of this invention will appear from the yfollowing description, taken in connection with the accompanying drawings in which:

FIG. 1 is a schematic view in side elevation of an arrangement of fuel oil flow paths in an oilrburner system embodying the features of the present invention, the same being illustrated in association with the standard components of an oil burner shown in broken lines;

FIG. 2 is a foreshortened fragmentary plan view of a heat exchanger forming a part of the oil burner system of the present invention, parts being broken away to disclose details of internal construction;

FIG. 3 is a fragmentary View in side elevation of an oil burner system showing an automatic air adjustment assembly embodying features of the present invention, portions being broken away to disclose details of internal construction;

FIG. 4 is a fragmentary view in front elevation as viewed from the right in FIG. 3 with portions broken away to disclose internal structural details;

t FIG. 5 isa schematic diagram of an electric circuit for the oil burner system of the present invention; i FIG. 6 is a foreshortened schematic view in side eleva tion illustrating the use of thek oi-l burner system of t-he present invention in an environment which creates widely varying draft conditions in the firing chamber;

FIG. 7 is a fragmentary sectional view in side elevation of the oil yburner system of FIG. 6; and

FIG. 8 is a schematic diagram of an electric circuit for use in the oil burner system of FIGS. 6 and 7.

Referring particularly to FIG. 1 of the drawings, the

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oil burner system of the present invention includes =a hollow housing 10 having an opening through its front side which communicates with the rearward end of a hollow elongated air tube 12 which is open at both ends. On one of the lateral sides of the housing is supported a hollow cylindrical air intake cage 14 (FIGS. 3 and 4) the inner end of which -is in open communication with an enlarged air inlet opening in the side wall of the housing. A plurality of longitudinal slots 16 are provided in the cylindrical wall of the cage for the passage of air into the housing. The outer end of the cage is closed by an end wall 4which supports a fuel oil pump 18 (FIG. l).

The opposite lateral side wall of the housing supports an electric drive motor 20 the output driven shaft 22 of which extends laterally through the housing and lair intake cage for driving connection to the fuel oil pump. The intermediate portion of themotor shaft which traverses the housing supports an air fan 24 (FIGS. 3 and 4) typically of the squirrel cage type, for rotation therewith within the housing, to supply air under 'pressure forwardly through the air tube 12.

The foregoing assembly constitutes a typical light oil burner of the high pressure type, of which there are many makes and models commercially available from such sources as Automatic Burner Corporation (Model Nos. 62A; 96A; etc.), -and may others. Conventional light oil pumps employed in such burners are available from such sources as Sundstrand Hydraulics (Model Nos. I; H; etc.), Webster Electric (Type Nos. lRlll; 22Rl20; etc.), and others.

In accordance with the present invention the foregoing assembly is supported upon a hollow console box 26 in which is housed an oil heater tank 2S (FIG. l). The tank contains one or more electric heater elements 30 and a control thermostat 32 therefor Iby which to heat fuel oil to a predetermined temperature.

Fuel oil is delivered to the bottom end of the heater tank by means of the infeed conduit 34 which preferably communicates with the bottom end of an infeed reservoir 36 which, in turn, receives fuel oil from a storage source (not shown) through one of a pair of openings 38 and 40. The other opening serves to return fuel oil to the storage source. By this means the fuel oil may be circulated continuously or at least intermittently from and back to the storage source. This is desirable particularly when the fuel oil is of heavy grade (eg. No. 5 or PS 300), since these oils tend to separate when not in motion.

Circulation of oil from and back to the storage source, through the infeed reservoir, may be effected by use of an oil transfer pump, preferably of the positive displacement type. The pump may be arranged with its inlet connected to the supply source and its outlet connected to opening 3S, to deliver oil under pressure to the inlet reservoir, with opening 40 being connected through a pipe back to the supply source. Alternatively, the pump may be arranged with its inlet connected to opening 38 and its outlet connected back through a pipe to the supply source, with opening 40 being connected also to the supply source to deliver oil under partial vacuum to the inlet reservoir.

It will be understood, of course, that in the event circulation of fuel oil from and back to the supply source is not required, the infeed reservoir may be omitted and the infeed conduit connected directly to the supply source.

The upper end of the heater tank 28 communicates through the main feed conduit 42 with the inlet reservoir of the oil pump 18. A thermo-syphon return conduit 44 communicates this inlet reservoir of the pump with the bottom end of the heater tank. Thus, heated oil in the heater tank rises through the main'feed conduit 42 into the inlet reservoir of the pump where some of its heat is transferred to the metal components of the pump, thereby heating the latter. The partially cooled oil then returns to the bottom end of the heater tankthrough the return conduit 44. This thermo-syphon circulation of oil is maintained continuously while the pump is inoperative. By this means.k the oil, if of the heavy type, is kept hot, substantially at or slightly above its ignition temperature, and the fuel oil pump is also maintained in heated condition. The viscosity of the heated oil, even though it may be heavy grade, is reduced substantially to the viscosity of light oil, and therefore the fuel pump may be of the light oil type exemplified hereinbefore.

An elongated hollow heat exchanger 46, closed at both ends, is confined within the hollow housing and extends forwardly through the air tube 12, terminating yadjacent the front open end of the latter. 48 (FIG. 2) of the heat exchanger supports at least one hollow spray nozzle adapter 50 in 'heat conductive relation thereto. In the embodiment illustrated, two such adapters 'are provided for mounting a pair of conventional light oil spray nozzles S2 and 54 (FIG. 1) in heat con-- ductive relation thereto. The forward portion of the internal bore of each adapter is Vvthreaded to receive the threaded shank 56 of a spray nozzle, and the intermediate portion of the bore is proportioned to freely receive the rea-rward'screen portion 58 of the nozzle. The rearward portions of both adapter bores are threaded to receive the forward threaded-ends of the high pressure outfeed conduits 60 and 62. The outfeed conduits extend through the rear wall of the heat exchanger for connection through the associated solenoid valves 64 and 66, respectively, to the main outfeed conduit 68. This conduit is connected to the main high pressure outlet of the fuel pump 18.

Means is provided for circulating the heated oil from the heater tank 28 to the forward end of the heat exchanger 46 and then back to Ithe heater tank, for the purpose of heating the spray nozzles and the associated high pressure vfeed conduits to a temperature close to the ignition temperature of the oil. In the embodiment illustr'ated, an auxiliary high pressure outlet of the fuel pump 18 is connected to one end of the circulating outfeed conduit 70. The forward portion of this conduit is confined within the heat exchanger and terminates at its forward end closely adjacent the front wall 48 of the heat exchanger. Accordingly, heated oil is pressure fed from the auxiliary outlet of the pump to the forward end of the heat exchanger, where a portion of its heat is transferred through the front wall of the heat exchanger and the nozzle adapters to the spray nozzles. The heated oil ills the heat exchanger, transferring an additional portion of its heat to the high pressure outfeed conduits, and the oil then is returned to the heater tank through a return conduit 72 and a hollow housing 74 containing a thermostat -bulb 76. This remote bulb is operatively connected vto a single pole, double throw thermostat switch 76 (FIG. 5). Many commercial types are available, such as the Honeywell Aquastat Model L6008A.

Although the return from the thermostat housing 74 to the heater tank 28 may be direct, the preferred embodiment illustrated utilizes the returning oil to provide an additional important function. Thus, the outlet from the thermostat housing 74 is connected through the conduit 78 to the inlet of the aspirator element Sti the suction end 82 of which is connected through the return conduit 84 to the main infeed conduit 34. Thus, as the oil returns from the heat exchanger to the heater tank through the aspirator, the partial vacuum created in the main pump inlet conduit 42 is sufficient to strip the oil being fed to the pump of the air and other volatiles entrained in it.

These volatiles travel with the returning oil in the conduit to the point where it enters the main infeed conduit, and there the volatile-s travel upward toward the infeed reservoir. If the reservoir is provided for the circulation of oil from and to the supply source, the volatiles are carried b'ack to the supply source from whence they are exhausted to the atmosphere. In the event no provision The front wall Y is made for circulating the storage oil and the infeed conduit is connected to the source for gravity feed, the volatiles will travel upward to the elevated storage source for evacuation to the atmosphere.V

It is Well known that efficient combustion of fuel oils Irequires proper proportioning of oil and Iair. Accordingly, means is provided in the embodiment illustrated for adjusting automatically the amount of air delivered to the front end of the air tube, depending upon whether one 0r both nozzles S2 and 54 are feeding fuel. The means by which this is accomplished is illustrated in FIGS. 3 and 4. Mounted across the air inlet opening in the lateral side wall of fthe housing 10 are a pair of butterfly vanes 86 supported for .pivotal movement by the shafts 88 jou-rnaled in the spaced bearings 90 secured to the air inlet cage 14. The shafts extend through the bearings and are secured against axial displacement at one end by the collar members 92 and set screws 94, and at the opposite ends by the disc members 96 and set screws 98.

The -disk members are interconnectedA pivotally by the link 160 in such manner that the shafts are caused to rotate in opposite directions. A second link 102 pivotatlly connects one of the disk members to a reciprocating abutment block 104. Secured t-o this block is an elongated rod 106 which extends downward through a guide tube 168 into Ithe hollow console box 26. The guide tube extends through the upper wall-of the console box and is secured thereto by means yof the clamping nuts 110. The lower end of the rod is secured to one end of a coil spring 112, the opposite end of which is secured to the reciprocating armature 114 of an electric solenoid 116 secured within the console.

Surrounding the rod 106 between the underside of the abutment block 104 and the facing end of the guide tube 108 is a coil spring 118 which functions to urge the abutment block resiliently upward away from the solenoid 116, thus moving the solenoid armature to its retracted position. A protective sleeve 120 is secured to the abutment block and surrounds the coil spring and upper portion of the guide tube, to prevent entrance of dirt and other material which might inhibit free movement of the rod.

The limits of reciprocative movement of the abutment block are adjustable by means of the adjustment screws 122 and 124 which are threaded through tapped openings in the spaced extensions of the bracket 126 secured -to the side wall of the housing. The screws face each other and intercept the abutment block 104 during `its movement.

The upper adjustment screw 122 limits upward movement of the abutment block, and hence establishes the limit of arcuate movement of the butterfly vanes 86 in the closing direction of the latter, thereby regulating the minimum amount of air to be delivered to the front end CII of the air tube 12. The lower adjustment screw 124 limits downward movement of the abutment block .and hence: the limit of arcuate movement of the butterfly vanes in1 the opening direc-tion, thereby regulating the maximum. amount of air delivered to the front end of the air tube.

The c-oil spring 112 which interconnects the rod 106 and the solenoid armature 114 functions to permit the armature to. extend fully into the solenoid coil, upon activation of the latter, regardless of the degree of downward move-v ment of the abutment block as determined by the setting; of the lower adjustment screw 124;

When the butterfly vanes are in the open position of adjustment to provide the desired amount yof air for proper combustion of fuel oil fedV from both nozzles 52 and 54, the llame pattern projects properly in a concentric pattern about the longitudinal axis of the air tube 12. However, it has been discovered that when only the upper nozzle 52 is active to providering at low feed rates, for example two or three gallons per hour, with the butterfly vanes adjusted to restrict the air inlet opening correspondingly, this minimum amount of air tends to be ejected by the rotary fan 24 along one side only of the air tube 12. The

resulting flame pattern projects angularly forward away from the longitudinal axis of the air tube, thereby impinging on one side wall of thev firing chamber to a greater extent than on the opposite wall. This mode of operation adversely affects the efficiency of the heating system and ultimately results in damage to the firing chamber.

Means is provided to overcome this condition of angularly offset flame pattern at low firing rates. In the embodiment illustrated this means comprises an elongated air directing baille 126 which is positioned within the housing between the air fan 24 and the inner surface of the housing and is mounted for pivotal adjustment by means of the stem 128 which extends through an opening in the housing. The outer portion of the stem is -threaded for reception of the clamping nut 130, by which -to secure the bafe in adjusted position. The outermost portion of the stem is provi-ded with a pair of opposed flat sides 132 parallel to the plane of the baie. These flat sides serve to provide means for engaging the stem with a wrench or other tool for rotating the stem, Iand also serve as an index pointer by which the angular position of the baffle may be ascertained. It will be understood that the outer end of the stem may be provided with a hand knob and index pointer, or any other suitable means desired for the purpose.

As the air adjusting baffle 126 is pivoted about the stem, the flame pattern emitted from the nozzle will be seen to swing arcuately across the longitudinal axis of the air tube. Accordingly, it is -a simple matter to bring the llame pattern into precise axial symmetry with the air tube and firing chamber.

The operation of the burner system described hereinbefore now will be explained with reference to the circuit diagram illustrated in FIG. 5. For purposes of this description it will be assumed that heavy oil will be fired and that the upper land lower spray nozzles 52 and 54 are selected to provide feed rates of three and seven gallons per hour, respectively. Let it be assumed, further, that the heater elements 30 in the heater tank 28 have been activated through electric supply lines L-1 and L-2 to bring the oil in the heater tank to the desired elevated temperature through appropriate operation of the associated thermostat 32. For example, if the ignition -temperature of the oil is determined to be about 190 F., the thermostat 32 is set to maintain the temperature of oil in the tank at about 200 F.

If the heating unit with which the oil burner system is associated is employed to heat a building to a desired temperature controlled by a room thermostat 140, the latter is connected to the terminals 142 and 144 of the safety control unit 146, and the jumper 148 indicated by dash lines is omitted. Various commercially available safety controls may be employed, the control illustrated being Honeywell Model RA 890B.

With the room thermostat 140 being employed for control, the boiler limit controls 150 and 152 for low and high pressures or temperatures, respectively, indicated by dotted lines, are omitted.

Let it be assumed that the -main on-off switch 154 is closed, energizing the transformer 156 in the safety control unit, thus activating the electronic network 158 and flame relay 160. Closure of contacts B of the llame relay completes the electric circuit of the transformer 162, whereupon its secondary winding 164 activates the check relay 166. Closure of the check relay contacts forms a holding circuit for said relay, bypassing contacts B of the flame relay 160. The secondary winding 168 of transformer 162 provides a negative bias to the control grid of an electron tube in the electronic network to deenergize the llame relay 160 and return its contacts to the positions illustrated.

Assuming that the spray nozzles 52 and 54 are below desired temperature (e.g. 190 F.), the thermostat bulb 76 therefore is no-t satisfied and the thermostat switch contacts 170 and 172 are closed, as illustrated. Accordingly, the electric circuit of the relay 174 is completed, closing its associated contact 176 and energizing the burner motor 2 0 to circulate heated oil from the heater tank 28 through the heat exchanger 46 and back past the bulb 76 to the heater tank. When the circulating oil has brought the spray nozzles to desired temperature, satisfying the bulb 76, the thermostat switch transfers, opening contacts 170 .and 172 to deenergize relay 174 and burner motor 20, and to close the thermostat contacts 172 and 178.

If the room thermostat is satisfied, opening its switch contacts, the load relay 180 in the safety control unit 146 remains deenergized, as d-oes the electronic network 158, thus providing no completed circuit through the thermostat contacts 172 and 178. Accordingly, the burner motor 20 remains deenergized until the oil at the thermostat bulb 76 cools suiciently to transfer the thermostat switch back to close the-contacts and 172.

Let it now be assumed that the room thermostat 140 is not satised and therefore its switch contacts are closed. The load relay in the safety control unit energizes through the closed contact A of the inactive ame relay 160, thence through the safety switch heater 182 yand t'he energized secondary winding 164 of the transformer 162, through the safety switch 184 (reset). Upon energization of the load relay, its contact A closes to complete the electric -circuit of the low feed oil control solenoid 64 and the ignition transformer 186 through terminals 188 and 190 of the safety control unit and the closed contacts 172 and 178 of the thermostat switch 76. Relay 192 also is closed through this san-1e circuit, closing its associated contact and energizing the burner motor 20 to supply heated oil under pressure to the low feed spray nozzle 52 for ignition by the electric spark established across the electrodes 186 by the transformer 186.

Also upon activation of the load relay 180, closure of its contact C completes the electric circuit of the flame detecting eye 194 and the electronic network. If the flame is not established within a predetermined time and thus is not sensed by the eye, the safety switch heater 182 functions to break the circuit of the safety switch 184 (reset), whereupon the load relay is deenergized. The low feed oil solenoid, ignition transformer and relay 192 thus are deactivated along with the burner motor 20.

On the other hand, if the low feed flame is established and detected by the eye within the predetermined. time, the llame relay 166 becomes energized through the electronic circuit. Activation of the flame relay opens its associated contact A, breaking the electrical circuit of the safety switch heater 182. Simultaneously, the flame relay contact C closes to complete the electric circuit of the high oil feed solenoid 66 and air adjustment solenoid 116 through terminals 196 and 190. Heated oil under pressure thus is delivered through the lower spray nozzle 54 for ignition by the flame already established, to provide maximum ring rate.

In the aforementioned illustration, wherein the low feed nozzle `52 feeds 3 gallons per hour and the high feed nozzle 54 feeds 7 gallons per hour, the maximum firing rate is l0 gallons per hour.

In the event the burner system is being used to fire a boiler to develop hot water or steam, the terminals 142 :and 144 of the safety control unit are jumpered, as indicated -at 148, to short the room thermostat 140, .and the low and high boiler limit control switches 150 and 152 are employed. Thus, the low boiler limit control switch 150 is connected between contact 172 of the thermostat switch '76 and line L-l, and the high boiler limit control switch 152 is connected between terminal 196 of the safety control unit and the hot terminals of the Ihigh oil feed solenoid 64 and air adjustment solenoid 116. The low limit control 150 may, for example, be .adjusted to open when boiler Steam pressure reaches 95 p.s.i. and to close when the steam pressure drops to 85 p.s.i., and the high limit control 152 adjusted to open when boiler steam pressure reaches 90 p.s.i. and to close when the steam p-ressured rops to 85 p.s.i.

Assuming that the boiler steam pressure is below 85 p.s.i. so that both -of the boiler limit control switches are closed, the burner motor 20 is energized through contacts 170 and 172 of `the thermostat switch `and the closed Contact of the activated relay 176, to circulate heated oil through the heat exchanger 46 to bring the nozzles up to the desired ignition temperature. When this condition is reached, the thermostat switch transfers to close the contacts 172 and 178 and complete the electric circuit of the low oil feed solenoid 64, the ignition transformer 188 and relay 192 through the closed contact A of the activated load relay 180. Closure of the contacts :associated with relay 192 transfers the electric circuit of the burner 1motor to line L2, and oil is fed under pressure to the low feed spray nozzle 52 for ignition.

If the flame is not established within the predetermined time, the safety switch heater 182 functions to open the safety switch 184 (reset) and deactivate the burner,.|as previously described. However, if the flame is established within the predetermined time, the flame relay 160 becomes energized, opening its contact A to break the circuit of the safety switch heater, and closing its contact C to complete the electric circuit of the high oil feed solenoid 66 and `air adjustment sholen'oid 116, also as previously described.

When the burner system has operated for a time sutlcient to bring the steam pressure to 90 p.s.i., the high boiler limit control switch 152 opens to deactivate the high oil feed solenoid 66 vand air adjustment solenoid 116. The burner system continues to function, but only on the low feed oil flame supplied through the upper spray nozzle 52. Thus, if steam pressure is being utilized at a low rate, it may be maintain-ed over substantial period of time by the low feed flame only, thereby maintaining maximum burner eciency over an extended peri od of time. On the other hand, if steam pressure is being utilized at `a maximum rate, the high boiler limit control switch 152 again will close to `activate the high oil feed solenoid and air adjustment solenoid, 'as will be apparent.

In the foregoing illustration the air `adjustment solenoid 116 is activated simultaneously with the high oil feed solenoid 66 to increase the volume of air through the air tube 12 to correspond with the increase in oil feed through the lower spray nozzle 54, for optimum combustion. The air adjustment solenoid also may be utilized in a different manner, illustrated in FIGS. 6, 7 and 8. FIG. 6 illustrates a lumber dry kiln in one large compartment 200 of which lumber is introduced for drying. This compartment communicates with a heat supply compartment 202 through an opening 204 in the separating wall 206. Supported within this opening is a fan 208 mounted for reversible rotation by the elongated shaft 210 which extends through the heat supply compartment into a 'burner room 212 which is separated therefrom by the wall 214. The shaft 210 is connected to the output end of a gear reduction unit 216 the input end of which is connected to the reversible electric motor 218.

Thus, when the motor is activated to rotate in `one direction, the fan 208 is caused to drive heated air from the heat supply compartment 202 into the dry kiln compartment 200 where it is circulated to extract moisture from the lumber and then exhausted to the atmosphere. When the electric motor is activated to rotation in the opposite direction, the fan functions to drive air from the dry kiln compartment 200 into the heat supply compartment 202 from whence it is exhausted to the atmosphere.

This reversing air flow procedure is repeated throughout the drying time, and has been found to provide efi8 fective drying of lumber While upgrading the latter by prevention of checking.

Heat is supplied to the heat compartment 202 by means of the oil burner Isystem described here before. In the embodiment illustrated in FIGS. 6 and 7, the burner is mounted in the burner room 212, as by means of the support 220, and its air tube 12 communicates with the interior of a firing chamber 222. This chamber is open at its front end and is lined about its inner circumference and its rear wall with brick 224 or other suitable refractory material. The open front end of the firing tube communicates with the heat supply compartment 202.

It is to be noted that when the fan 208 is driven to drive heated air from the heat supply compartment 202 into the dry kiln compartment 200, there is created within the heat supply compartment a pressure which is lower than the atmospheric pressure existing in the burner room 212. Accordingly, more air is caused to be forced forwardly through the burner air tube 12 than normally is delivered when the 'pressures are equal. Thus, it becornes necessary to `adjust the air control butterfly vanes 86 to a more closed position, by appropriate adjustment of the upper adjustment screw 122 (FIG. 3).

Conversely, when the fan 208 is driven in the direction to drive air from the dry kiln compartment 200 into the heat supply compartment, there is developed in the latter a condition of pressure which exceeds the atmospheric pressure existing in the burner room 212. Accordingly, a back pressure is impressed upon the front end of the burner air tube 12 which counteracts the effect of the burner air fan 24, with the result that a lesser quantity of air is supplied through the burner air tube for proper combustion of fuel oil.

Furthermore, this back pressure is of sufficient magnitude to cause the burner flame to recede into the burner air tube, resulting in disintegration of the forward end of the latter as well as of the ignition electrode assembly.

Accordingly, it is necessary under this condition to supply an even greater volume of air forwardly through the burner air tube to more than counterbalance the back pressure.

Referring to FIG. 8 of the drawings, the reversible electric drive motor 21S for the fan 208 is connected to the terminals 226 of a source of electric supply through a motor reversing switch unit 228 of conventional 4construction. The air control solenoid 116 also is connected to the electric supply through this motor reversing switch unit in such manner that when the motor 218 is being driven in the direction to cause the fan 208 to drive air from the heat supply compartment 202 into the dry kiln compartment 200, the air control solenoid 116 is deactivated and the buttery vanes 86 are in position providing a predetermined minimum of air to the fan 24 and burner air tube 12. However, when the motor reversing switch unit is operated to reverse the direction of the motor 21S to drive air from the dry kiln compartment 200 into the heat supply compartment 202, the air adjustment solenoid 116 also is activated to move the butterfly vanes 86 to the desired position of open adjustment to admit more air to the burner fan 24 and air tube 12.

Additional means also may be provided to further reduce the effect of the aforementioned back pressure. In the embodiment illustrated, the firing chamber is surrounded by a supplementary air tube 230 having a closed rear wall coextensive with the rear wall of the firing chamber. The air tube is spaced concentrically about the firing chamber, providing an annular air chamber 232 therebetween, and extends forwardly of the front end of the firing chamber through the wall 214 separating the heat supply compartment 202 and burner room 212. A side inlet 234 in the air tube 230 communicates with an air fan 236 by which air is delivered under pressure to the air chamber, from whence it is ejected in a spiral manner forwardly into the heat supply compartment 202, to counteract the back pressure existing in the latter.

The front end of the firing chamber 222 preferably is constricted by means of a circular disc 238 of refractory material having a diameter slightly smaller than the internal diameter of the tiring chamber and supported concentrically with respect to the latter by such means as the spacer blocks 240. There is thus provided an annular opening at the forward end of the ring chamber through which the gases of combustion are ejected into the heater compartment. The air spiralling forward past the front end of the firing chamber 222 creates an area of reduced pressure which functions to draw the combustion gases outward from the firing chamber.

It has been found that the foregoing arrangement by which the air adjustment solenoid is controlled in accordance with the direction of rotation of the drive motor 218, and hence in accordance with two different conditions of draft impressed upon the burner, provides the proper amount of air for optimum fuel combustion may be maintained at all times. In this regard it is to be understood that the oil is delivered only through one solenoid valve 64 and spray nozzle 52 of appropriate maximum capacity, the lower solenoid valve 66 and spray nozzle assembly being omitted.

Further, it has been found that the foregoing arrangement is effective to prevent the flame from receding into the air tube l2, thus eliminating the cost of replacement of the burner tube assembly and the consequent cost resulting from plant'shut down.

From the foregoing it will .be appreciated that the present invention provides an oil burner system which affords many advantages. The air adjustment system m-ay be utilized in conjunction with the burnin-g of light or heavy fuel oils to provide automatic adjustment of air for the proper combustion at two different firing rates, or the firing at a single rate under two different conditions of draft. The llame adjustment baffle may be utilized in the tiring of light or heavy fuel oils at low rates to insure proper positioning of the flame pattern concentric about the longitudinal axis of the air tube. The aspirator feature of the burner system affords use of the latter in the firing of crude oil and crank case oil with complete reliability and safety by insuring the removal of volatiles from the burner system. The burner system may be constructed of components generally limited to burners designed for firing light oil only, while accommodating the burning of heavy oils with maximum efficiency and reliability.

It will be .apparent to those skilled in the art that various changes may be rnade in the size, number and arrangement of parts and other details of construction described hereinbefore, without departing from the spirit of this invention and the scope of the appended claims.

Having now described my invention and the manner in which it may be used, what I claim as new and desire to secure by Letters Patent is:

1. In an oil burner system including a hollow housing having an air inlet opening, a burner air tube having an open front end and communicating at its rear end with the interior of the housing, and blower means in the housing for supplying air under pressure to the front end of the air tube, the combination therewith of y (a) air control means mounted movably on the housing adjacent the air inlet opening for adjustment between an open position restricting the inlet opening to a predetermined minimum degree for delivering a predetermined maximum amount of air to the blower means, and a closed position restricting the inlet opening to a predetermined maximum degree for delivering a predetermined minimum amount of air to the blower means, and

(b) electrically actuated drive means for the air control means, the drive means being operable upon actuation to move to a fixed position,

(c) resilient means interengaging the drive means and .air control means for relative movement therebetween and urging the latter normally -to one of said open and closed positions, and

(d) adjustable stop means operatively engaging the air control means for varying the limits of movement of the latter, whereby to vary the open and closed positions of the air control means and therefore the maximum and minimum amounts of air to the blower means.

2. The combination of claim 1 including (a) a pair of oil spray nozzles positioned adjacent the open front end of the burner air tube,

(b) a pair of oil feed conduits communicating one with each spray nozzle,

(c) a pair of electrically actuated control valves each releasably communicating one of the cil feed conduits with a pressure outlet of the oil pump means, and

(d) electric circuit means for activating simultaneously the electrically .actuated air -control drive means and one of the electrically actuated oil control valves.

3. The combination of claim 1 including (a) a heating -chamber communicating with the burner air turbe and adapted to be hea-ted by the oil burner,

(b) electrically actuated draft control means associated with the heating chamber for varying the draft therein between high and low limits, and

(c) electric circuit means connecting the electrically actuated air control drive means and draft control means for moving the air control means to its open position when the draft is at its low limit and for moving the air control means to its closed position when the draft is at its high limit.

4. In an oil burner system including oil pump means, lan oil heat tank adapted to receive oil from a supply, heater means for heating oil in the heat tank to a predetermined elevated temperature, a hollow heat exchanger within the burner air tube having a closed front end positioned adjacent the open front end of the burner air tube, an oil spray nozzle mounted in heat conductive relationship with the front end of the heat exchanger, an oil feed conduit communicating with the spray nozzle and connected to a pressure outlet of the oil pump means, oil circulating conduit means interconnecting the heat tank and heat exchanger through the oil pump means for circulating oil from the heat tank through the heat exchanger and back to the heat tank, and oil inlet conduit means communicating with the oil circulating conduit means at the highest point of the return side of the latter from the oil pump means to the tank, the combination therewith of aspirator means having an inlet end connected in the oil circulating conduit means -on the outlet side of the oil pump means, an outlet end connected in the oil circulating conduit means adjacent and ahead of the loil inlet conduit means, and a suction port connected in the oil circulating conduit means on the inlet side of the oil pump means, for removing volatiles from the oil and passing them upward through the oil inlet conduit means.

5. An oil burner system comprising (a) a hollow housing having an air inlet opening,

(b) a burner air tube having an open front end and communicating at its rear end with the interior of the housing,

(c) rotary blower means in the housing for supplying air under pressure to the front end of the air tube,

(d) oil pump means,

(e) electric motor means operatively connected to the blower means and pump means,

(f) a pair of oil spray nozzles positioned adjacent the open front end of the burner air tube,

(g) a pair of oil feed conduits communicating one with each spray nozzle,

(h) a pair of electrically actuated control valves each releasably communicating one of the oil feed conduits with a pressure outlet of the oil pump means,

(i) air control means mounted movably on the housing adjacent the air inlet opening for adjustment between an open position restricting the inlet opening to a predetermined minimum degree for delivering a predetermined maximum amount of air to the blower means, and a closed position restricting the inlet opening to a predetermined maximum degree for delivering a predetermined minimum amount of air to the blower means,

(j) electrically actuated drive means for the air control means, the drive means being operable upon actuation to move to a fixed position,

(k) resilient means interengaging the drive means and air control means for relative movement therebetween and urging the latter normally to one of said open and closed positions,

(l) adjustable stop means operatively engaging the air control means for varying the limits of movement Of the latter, whereby to vary the open and closed positions of the air control means and therefore the maximum and minimum amounts of air to the blower means, and

(m) electric circuit means for activating simultaneously the electrically actuated air control drive means and one of the electrically actuated control valves.

6. An oil burner system comprising (a) a hollow housing having an air inlet opening,

(b) a burner air tube having an open front end and communicating at its rear end with the interior of the housing,

(c) blower means in the housing for supplying air under pressure to the front end `of the air tube,

(d) oil pump means,

(e) electric motor means operatively connected to the blower means and pump means,

(f) an oil heat tank adapted to receive oil from a Supply,

(g) heater means for heating oil in the heat tank to a predetermined elevated temperature,

(h) a hollow heat exchanger within the burner airtube having a closed front end positioned adjacent the open front end of the burner air tube,

(i) a pair of oil spray nozzles mounted in heat conductive relationship with the front end of the heat exchanger,

(j) a pair of `oil feed conduits communicating one with each spray nozzle and extending rearwardly through the heat exchanger,

(k) a pair of electrically actuated control valves each releasably communicating one of the oil feed conduits with a pressure outlet of the oil pump means,

(l) air control means mounted on the housing adjacent the air inlet opening for movement between an open position restricting the inlet opening to a predetermined minimum degree and a closed position restricting the inlet opening to a predetermined maximum degree,

(rn) electrically actuated drive means engaging the air control means for moving the latter and (n) electric circuit means for activating simultaneously the electrically actuated air control drive means and one of the electrically actuated control valves.

7. The system of claim 6 including adjustable stop means operatively engaging the air control means for varying the open and closed positions of the air control means.

The system of claim 6 including flame control bathe means mounted in the housing adjacent the blower means for adjustment angularly with respect to the rotational axis of the latter, for adjusting the llame pattern with respect to the longitudinal axis of the burner air tube.

9. The system of claim 6 including (a) oil circulating conduit means interconnecting the heating tank and heat exchanger through the oil pump means for circulating oil from the heat tank through the heat exchanger and back to the heat tank,

(b) oil inlet conduit means communicating with the oil circulating conduit means at the highest point of the return side of the latter from the oil pump means to the heat tank, and

(c) aspirator means having an inlet end connected in the oil circulating conduit means on the outlet side of the oil pump means, an outlet end connected in the oil circulating conduit means adjacent and ahead of the oil inlet conduit means, and a suction port connected in the oil circulating conduit means on the inlet side of the oil pump means, for returning volatiles from the oil and passing them upward through the oil inlet conduit means.

1t?. The system of claim 9 wherein the oil inlet conduit means includes an inlet reservoir having an outlet opening communicating with the oil circulating conduit means, and a pair of vertically spaced openings above the outlet opening for connection to a supply source of oil for circulating oil from and back to the supply source.

11. For use with a heating chamber adapted to be heated by an oil burner, electrically actuated reversible blower means communicating with the heating chamber for varying the draft in said chamber between high and low limits, the electrical actuator having an electric circuit, and electrical control means in said electric circuit for controlling the reversible operation of the blower means, an oil burner including (a) a hollow housing having an air inlet opening,

(b) a burner air tube having an open front end adapted to communicate with the heating chamber and communicating at its rear end with the interior of the housing,

(c) `blower means in the housing for supplying air under pressure to the front end of the air tube,

(d) air control means mounted movably on the housing adjacent the air inlet opening 4for adjustment between an open position restricting the inlet opening to a predetermined minimum degree for delivering a predetermined maximum amount of air to the blower means, and a closed position restricting the inlet opening to a predetermined maximum degree for delivering a predetermined minimum amount of air to the blower means,

(e) electrically actuated drive means engaging the air control means for moving the latter, and

(f) electrical conductor means connected to the electrical actuator for the drive means and adapted for connection to the electrical control means for the reversible blc-wer means for activating the air cOntrol drive means simultaneously with activation of the reversible blower means to one of its reversible directions for moving the air control means to its open position when the draft is at its low limit and for moving the air control means to its closed position when the draft is at its high limit.

12. In combination with a heating chamber adapted to be heated by an oil burner, electrically actuated reversible blower means communicating with the heating chamber for varying the draft in said chamber between high and low limits, the electrical actuator having an electric circuit, and electrical control means in said electric circuit for controlling the reversible operation of the blower means, an oil burner including (a) a hollow housing having an air inlet opening,

(b) a burner air tube having an open front end communicating with the heating chamber and communieating at its rear end with the interior of the housing,

(c) blower means in the housing for supplying air under pressure to the front end of the air tube,

(d) air control means mounted movably on the housing adjacent the air inlet opening for adjustment 13 14 between an open position restricting the inlet openat its low limit for moving the air control means ing t0 a predetermined minimum degree for deliverto its closed position when the draft is at its high ing a predetermined maximum amount of air to the g limit blower means, and a closed position restricting the inlet opening to a predetermined maximum degreey 5 References Cited by the Examiner for delivering a predetermined minimum amount of UNITED STATES PATENTS air to the blower means, (e) electrically actuated drive means engaging the air 0801289 5/1937 Muvame et al- 158-28 control means for moving the latter, and 2,223,435 12/1940 Wlulams 158-36 (f) electrical conductor means connecting the elec- 10 2,315,412 3/1943 Gahlm'be'ck 158-28 X trical actuator for the drive means to the electrical 2,815,900 l2/ 1957 Smith 158-76 X control means for the reversible blower means for 3,070,149 12/ 1962 Irwin 15S-28 X activating the air control drive means simultane- 3,196,925 7/1965 Trabilcy 158--36 ously with activation of the reversible blower means 3,211,439 10/1965 Fahlberg 263-19 to one of its reversible directions for moving the 15 air control means to its open position with the draft JAMES W. WESTHAVER, Primary Examiner. 

1. IN AN OIL BURNER SYSTEM INCLUDING A HOLLOW HOUSING HAVING AN AIR INLET OPENING, A BURNER AIR TUBE HAVING AN OPEN FRONT END AND COMMUNICATING AT ITS REAR END WITH THE INTERIOR OF THE HOUSING, AND BLOWER MEANS IN THE HOUSING FOR SUPPLYING AIR UNDER PRESSURE TO THE FRONT END OF THE AIR TUBE, THE COMBINATION THEREWITH OF (A) AIR CONTROL MEANS MOUNTED MOVABLY ON THE HOUSING ADJACENT THE AIR INLET OPENING FOR ADJUSTMENT BETWEEN AN OPEN POSITION RESTRICTING THE INLET OPENING TO A PREDETERMINED MINIMUM DEGREE FOR DELIVERING A PREDETERMINED MAXIMUM AMOUNT OF AIR TO THE BLOWER MEANS, AND A CLOSED POSITION RESTRICTING THE INLET OPENING TO A PREDETERMINED MAXIMUM DEGREE FOR DELIVERING A PREDETERMINED MINIMUM AMOUNT OF AIR TO THE BLOWER MEANS, AND (B) ELECTRICALLY ACTUATED DRIVE MEANS FOR THE AIR CONTROL MEANS, THE DRIVE MEANS BEING OPERABLE UPON ACTUATION TO MOVE TO A FIXED POSITION, (C) RESILIENT MEANS INTERENGAGING THE DRIVE MEANS AND AIR CONTROL MEANS FOR RELATIVE MOVEMENT THEREBETWEEN AND URGING THE LATTER NORMALLY TO ONE OF SAID OPEN AND CLOSED POSITIONS, AND (D) ADJUSTABLE STOP MEANS OPERATIVELY ENGAGING THE AIR CONTROL MEANS FOR VARYING THE LIMITS OF MOVEMENT OF THE LATTER, WHEREBY TO VARY THE OPEN AND CLOSED POSITIONS OF THE AIR CONTROL MEANS AND THEREFORE THE MAXIMUM AND MINIMUM AMOUNTS OF AIR TO THE BLOWER MEANS. 